We propose to continue our study of enzymatic catalysis by computational methods. In previous work we have shown feasibility of predicting the energies of models of the transition state for hydrolysis of substrates or of potential substrates by chymotrypsin. Steric energies derived by molecular mechanics reproduce the experimental relative free energies of activation for three D-L pairs: for acetyltryptophan, for acetylphenylalanine, and for the Hein-Niemann "locked" substrate. The present study will evaluate more sophisticated models, a broader range of substrates, and other topics designed to provide more definitive procedures for the theoretical prediction of energies of intermolecular interactions of peptides and proteins.